# Scrapy settings for itcast project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://docs.scrapy.org/en/latest/topics/settings.html
#     https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://docs.scrapy.org/en/latest/topics/spider-middleware.html

BOT_NAME = 'itcast'

SPIDER_MODULES = ['itcast.spiders']
NEWSPIDER_MODULE = 'itcast.spiders'


# Crawl responsibly by identifying yourself (and your website) on the user-agent
# scrapy发送的每一个请求的默认UA都是设置的这个User-Agent
USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.129 Safari/537.36'
# USER_AGENT = 'itcast (+http://www.yourdomain.com)'

# Obey robots.txt rules
# 设置ROBOTS协议
# False表示忽略网站的robots.txt协议，默认为True
ROBOTSTXT_OBEY = False

# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32

# Configure a delay for requests for the same website (default: 0)
# See https://docs.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
#DOWNLOAD_DELAY = 3
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16
#CONCURRENT_REQUESTS_PER_IP = 16

# Disable cookies (enabled by default)
#COOKIES_ENABLED = False
# # 通过设置COOKIES_DEBUG=TRUE 能够在终端看到cookie的传递传递过程
# COOKIES_DEBUG=True

# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False

# Override the default request headers:
#DEFAULT_REQUEST_HEADERS = {
#   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
#   'Accept-Language': 'en',
#}

# Enable or disable spider middlewares
# See https://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'itcast.middlewares.ItcastSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'itcast.middlewares.ItcastDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
# 启用管道
ITEM_PIPELINES = {
   # 值表示距离引擎的远近，越近数据会越先经过：权重值小的优先执行
   'itcast.pipelines.ItcastPipeline': 300,
   # 开启保存到MongoDB数据库的管道
   'itcast.pipelines.MongoPipeline': 301,
   'scrapy_redis.pipelines.RedisPipeline': 400,
}

# 实现单机断点续爬
# 分布式去重的类
DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"
# 分布式的调度器   用来存储request对象的队列 （实现持久化-- 指纹  request持久化存储）
SCHEDULER = "scrapy_redis.scheduler.Scheduler"
# 是否进行持久化
SCHEDULER_PERSIST = True

REDIS_URL = "redis://127.0.0.1:6379"

# Enable and configure the AutoThrottle extension (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/autothrottle.html
#AUTOTHROTTLE_ENABLED = True
# The initial download delay
#AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
#AUTOTHROTTLE_MAX_DELAY = 60
# The average number of requests Scrapy should be sending in parallel to
# each remote server
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
# Enable showing throttling stats for every response received:
#AUTOTHROTTLE_DEBUG = False

# Enable and configure HTTP caching (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
#HTTPCACHE_ENABLED = True
#HTTPCACHE_EXPIRATION_SECS = 0
#HTTPCACHE_DIR = 'httpcache'
#HTTPCACHE_IGNORE_HTTP_CODES = []
#HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'
